This invention relates to an automatic assembly machine and, more particularly, to an assembly machine of the type having an automatic fastener driver for assembling screws, nuts and the like with workpieces.
Automatic assembly machines of the same general type as the machine of the present invention are disclosed in Dixon U.S. Pat. No. 3,279,045; Dixon U.S. Pat. No. 3,675,302; and Dixon U.S. Pat. No. 3,910,325. The fastener drivers of such machines include a rotary motor operable to drive a screwdriver bit, a socket wrench or other tool; the fasteners being fed one-by-one to the tool. The machines are used by moving the fastener driver horizontally to an appropriate position over a workpiece and then by moving the driver downwardly to effect assembly of the fastener with the workpiece. The fastener driver then is retracted upwardly and is repositioned horizontally to a different position over the workpiece preparatory to driving the next fastener.
In the machine disclosed in Dixon U.S. Pat. No. 3,675,302, the fastener driver is carried on an articulated support which permits the fastener driver to be swung to various positions over the workpiece. A template is employed to enable the machine operator to locate the fastener driver at precisely predetermined positions with respect to the workpiece. The template, however, is located below the workpiece and cannot be clearly viewed by the operator.
In some respects, the present assembly machine is similar to that disclosed in Dixon U.S. application Ser. No. 07/581,575, filed Sep. 11, 1990. In that machine, screws are blown one-by-one through a delivery tube to an internal chamber defined within a pair of opposing chuck jaws adapted to pivot between open and closed positions and normally biased to their closed positions. A power-rotated driver advances downwardly into engagement with the screw held by the jaws and causes the screw to cam the jaws to their open positions so as to permit driving of the screw. While the jaws maintain excellent control over the screw, the jaws are positioned in contact with or very close to the surface of the workpiece at the time the jaws are cammed open by the screw. If there is an obstruction or another screw closely adjacent the screw being driven, the jaws may be prevented from pivoting to their open positions.